Field of the Invention
This invention relates to a process for the production of power while using liquefied natural gas (LNG) and synthesis or fuel gas.
Liquefied natural gas (LNG) is generally brought in by tanker from remote sites and traditionally regasified by heat exchange with sea water. It is normally at atmospheric pressure at a temperature of about -240.degree. F. to -270.degree. F. and must be regasified before it can be used as a fuel. A single multi-component motive fluid was used as the liquefied natural gas exchange media in U.S. Pat. No. 3,479,832.
Raw synthesis gas, substantially comprising mixtures of H.sub.2, CO, CO.sub.2, N.sub.2, H.sub.2 O, H.sub.2 S and COS, as produced from sulfur-containing fossil fuels by contemporary partial oxidation processes, may have a methane content in the range of about nil to 2 mole percent and a maximum net heating value of about 300 BTU per standard cubic foot (SCF). In some applications, it is desirable to increase the methane content of the synthesis gas, for example to increase its gross heating value for use as fuel gas. In coassigned U.S. Pat. No. 3,688,438, synthesis gas was made having up to 26 volume percent of methane by the partial oxidation of a hydrocarbonaceous fuel using comparatively high steam to fuel weight ratios and no subsequent catalytic methanation step. Costly removal of water from the product gas was necessary. In coassigned U.S. Pat. No. 3,709,669, the synthesis gas leaving the partial oxidation gas generator is subjected to an additional step involving the catalytic water gas shift reaction to adjust the H.sub.2 /CO mole ratio to preferably 3 before catalytic methanation. In comparison with the prior art, by the subject invention a dry, sulfur-free, CH.sub.4 -enriched synthesis or fuel gas is produced without costly catalytic methanation or drying steps.